The mediating role of joint attention in the relationship between motor skills and receptive and expressive language in siblings at risk for autism spectrum disorder

Developmental associations between motor and communication outcomes in Fragile X syndrome: Variation in the context of co-occurring autism

LAY ABSTRACT

Fragile X syndrome (FXS), the leading heritable cause of intellectual disability, has a co-occurrence rate of autism spectrum disorder (ASD) estimated at ~60%. Children with FXS experience delayed achievement and slower development of key motor abilities, which happens to an even greater extent for children with both FXS and ASD. A multitude of studies have demonstrated that motor abilities are foundational skills related to later communication outcomes in neurotypical development, as well as in the context of ASD. However, these associations remain unexamined in FXS, or FXS + ASD. In this study, we aimed to determine the associations between early motor skills and their rate of development on communication outcomes in FXS. Furthermore, we investigated whether these associations varied in the context of co-occurring FXS + ASD. Results revealed within-FXS variation in the context of co-occurring ASD between some aspects of motor development and communication outcomes, yet within-FXS consistency between others. Findings provide evidence for variability in developmental processes and outcomes in FXS in the context of co-occurring ASD and offer implications for intervention.

Receptive language and receptive-expressive discrepancy in minimally verbal autistic children and adolescents

Among the approximately one-third of autistic individuals who experience considerable challenges in acquiring spoken language and are minimally verbal (MV), relatively little is known about the range of their receptive language abilities. This study included 1579 MV autistic children and adolescents between 5 and 18 years of age drawn from the National Database for Autism Research and the SFARI Base data repository. MV autistic children and adolescents demonstrated significantly lower receptive language compared to the norms on standardized language assessment and parent report measures. Moreover, their receptive language gap widened with age. Overall, our sample demonstrated significantly better receptive than expressive language. However, at the individual level, only about 25% of MV autistic children and adolescents demonstrated significantly better receptive language relative to their minimal expressive levels. Social skills explained a significant proportion of the variance in parent-reported receptive language skills, while motor skills were the most significant predictor of greater receptive-expressive discrepancy. Findings from this study revealed the heterogeneous language profiles in MV autistic children and adolescents, underscoring the importance of individualizing interventions to match their different communication strengths and needs and integrating multiple interconnected areas to optimize their overall development of language comprehension, socialization, and general motor skills.

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Associations Between Caregiver Stress and Language Outcomes in Infants With Autistic and Non-Autistic Siblings: An Exploratory Study

PURPOSE

Caregivers of autistic children present with high stress levels, which have been associated with poorer child outcomes in several domains, including language development. However, prior to this study, it was unknown whether elevated caregiver stress was associated with language development in infant siblings of autistic children (Sibs-autism), who are at increased likelihood of receiving a future diagnosis of autism and/or language impairment compared to infant siblings of non-autistic children. This study explored the degree to which, as well as the mechanisms by which, caregiver stress was linked with later language outcomes of Sibs-autism and infant siblings of non-autistic children (Sibs-NA).

METHOD

Participants were 50 infants (28 Sibs-autism; 22 Sibs-NA) aged 12-18 months at the first time point in this study (Time 1). Infants were seen again 9 months later, at 21-27 months of age (Time 2). Caregiver stress was measured via a validated self-report measure at Time 1. Caregiver language input, the putative mechanism by which caregiver stress may influence later language outcomes, was collected via two daylong recordings from digital recording (Language ENvironment Analysis) devices worn by the child at this same time point. Child language outcomes were measured via standardized and caregiver report measures at Time 2.

RESULTS

Several models testing hypothesized indirect effects of caregiver stress on later child language outcomes through caregiver language input were statistically significant. Specifically, significant indirect effects suggest that (a) caregivers with increased stress tend to speak less to their infants, and (b) this reduced language input tends to covary with reduced child language outcomes later in life for Sibs-autism and Sibs-NA.

CONCLUSIONS

This study provides new insights into links between caregiver stress, caregiver language input, and language outcomes in Sibs-autism and Sibs-NA. Further work is necessary to understand how to best support caregivers and optimize the language learning environments for infants.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21714368.

Prediction of Communicative Disorders Linked to Autistic Spectrum Disorder Based on Early Psychomotor Analysis

This systematic review evaluated psychomotor differences between children with and without siblings who have autism spectrum disorder (ASD), as well as the most reliable psychomotor skills that can help predict ASD and its associated language disorders. Literature from 2005 to 2020 was searched using the following databases: PubMed, Trip Medical Database, Cochrane, Web of Science, Science Direct, and Brain. A total 11 papers were included. Fine motor skills and joint attention displayed reliable results in order to predict ASD and its associated language disorders. The period between the first and the second year of life was considered the most appropriate one for the assessment of psychomotor skills. The best period to predict language disorders and ASD diagnosis is around 36 months old.

Early Motor Signs in Autism Spectrum Disorder

A growing number of literature data suggest the presence of early impairments in the motor development of children with autism spectrum disorder, which could be often recognized even before the appearance of the classical social communication deficits of autism. In this narrative review, we aimed at performing an update about the available data on the early motor function in children with autism spectrum disorder. Early motor impairment in these children can manifest itself both as a mere delay of motor development and as the presence of atypicalities of motor function, such as a higher rate and a larger inventory, of stereotyped movements both with and without objects. In the perspective of a timely diagnosis, the presence of early motor signs can be an important clue, especially in an individual considered at high risk for autism. Motor and communication (both verbal and non-verbal) skills are connected and a pathogenetic role of early motor dysfunctions in the development of autism can be hypothesized. From this, derives the importance of an early enabling intervention aimed at improving motor skills, which could also have favorable effects on other aspects of development.

The Vocabulary of Infants with an Elevated Likelihood and Diagnosis of Autism Spectrum Disorder: A Systematic Review and Meta-Analysis of Infant Language Studies Using the CDI and MSEL

Diagnoses of autism spectrum disorder (ASD) are typically accompanied by atypical language development, which can be noticeable even before diagnosis. The siblings of children diagnosed with ASD are at elevated likelihood for ASD diagnosis and have been shown to have higher prevalence rates than the general population. In this paper, we systematically reviewed studies looking at the vocabulary size and development of infants with autism. One inclusion criterion was that infants were grouped either pre-diagnostically as elevated or typical likelihood or post-diagnostically as ASD or without ASD. This review focused on studies that tested infants up to 24 months of age and that assessed vocabulary either via the parent-completed MacArthur–Bates Communicative Developmental Inventory (CDI) or the clinician-administered Mullen Scales of Early Learning (MSEL). Our systematic search yielded 76 studies. A meta-analysis was performed on these studies that compared the vocabulary scores of EL and TL infants pre-diagnostically and the scores of ASD and non-ASD infants post-diagnostically. Both pre- and post-diagnostically, it was found that the EL and ASD infants had smaller vocabularies than their TL and non-ASD peers, respectively. The effect sizes across studies were heterogenous, prompting additional moderator analyses of age and sub-group analyses of the language measure used (CDI or MSEL) as potential moderators of the effect size. Age was found to be a moderator both in the pre- and post-diagnostical groups, however, language measure was not a moderator in either diagnostic group. Interpretations and future research directions are discussed based on these findings.

Early trajectories of motor skills in infant siblings of children with autism spectrum disorder

Delays in motor development are not considered a core feature of autism spectrum disorder (ASD). Yet, recent studies of infant siblings of children with ASD suggest that early delays in motor skills may be associated with later delays in developmental areas considered to be core features of an ASD diagnosis. While these studies demonstrate the longitudinal association between core features and motor delays observed at single time points, there is considerable interest in studying the trajectories of motor development over the first 3 years of life. To accomplish this, we investigated early trajectories of motor development in a cohort of 499 infant siblings of children with ASD and 176 children with no family history of ASD. Data for the current study were drawn from the prospective, multi-site, Canadian Infant Sibling Study. We evaluated trajectories of fine and gross motor development over the first 3 years using group-based trajectory modeling. Our results show that membership for both fine and gross motor trajectory groups was related to expressive language skills, receptive language skills, ASD symptom severity scores, and diagnostic classification at age 3. These results provide evidence that the trajectory of a child's early motor development may have important prognostic implications in ASD.

Motor Influences on Communication: Comparisons Between Down Syndrome and Fragile X Syndrome

Motor skills, an important foundation for language and communication, are considerably delayed in children with Down syndrome (DS) and fragile X syndrome (FXS). However, the impact of these impairments on expressive and receptive communication and the phenotypic specificity of these associations remains unknown. Participants included 37 with DS and 37 age and developmentally matched children with FXS. Syndrome-specific motor and communication profiles emerged, with higher communication scores seen in the DS versus FXS on, but lower gross motor scores. Significant associations between domains of motor and communication were identified for both groups with additional phenotype-specific patterns. Findings demonstrate the importance of early motor abilities for communication in DS and FXS. Implications for phenotypic specificity and targeted intervention are discussed.

Play in Relation to Autism Traits in Young Children at Elevated Likelihood for Autism Spectrum Disorder

Play of younger siblings of children with autism spectrum disorder (ASD) (siblings; n = 44), very preterm children (preterms; n = 44), and children at typical likelihood for ASD (n = 36) was observed at 24 months. Children with ASD and atypical development engaged less in spontaneous (pre-)symbolic play than typically developing children. Total duration of spontaneous and elicited (pre-)symbolic play was associated with later ASD traits in siblings. However, no association between most play variables and ASD traits was found in preterms. This suggests possible different ASD-trajectories between siblings and preterms. Thus, spontaneous (pre-)symbolic play may be indicative of developmental challenges across several populations, and results highlight the need to move beyond studying only siblings in order to broaden our understanding of ASD.